It is known to provide wind shield structures about precipitation gauges. The purpose of the shield is to decrease wind velocity over the top of the precipitation gauge in a way that improves the efficiency and accuracy of precipitation measurement. Studies have shown that modifying the wind flow over and around precipitation measuring instruments reduces the likelihood of precipitation blowing over the top of the precipitation gauge and significantly increases the collection efficiency and accuracy of precipitation measurements.
One prior wind shield structure, called a double fence inter-comparison reference or DIFIR wind shield, includes two concentric fences with spaced apart slats designed to disrupt wind flow over the precipitation collector located at the center of the two concentric fences. This type of a wind shield structure is fairly expensive to install and maintain. Since the individual slats are stationary, the fence is subject to blockage by snow and blowing material.
In an effort to reduce costs and reduce the possibility of deflector blockage by snow and freezing precipitation, another prior “Alter Shield” design includes a moveable deflector fins. Aluminum or plastic wind deflector fins are pivotably mounted on ground support rods and held off the ground at a height slightly above the inlet height of the precipitation gauge by sturdy posts. Such a design, however, is extremely noisy since the wind deflector fins are blown together creating an environmental disruption. The pivoting deflector fins also have a tendency to blow horizontal in high wind conditions and they then become less effective in properly modifying wind flow over the precipitation gauge when most needed.